My friend wants me to help him out with a system and he wants to build a box out of steel welded under his truck so that the floor would be the front baffle with a port built into the box. The front would be the steel floor of the truck and the rest would be made out of like 1/8th or 1/4 inch steel. Would that sound bad? I kinda think that it would but im not a pro.
No it won't work and has been done before. Reason being is that most metals resonate within our audible hearing level, hence the metal would ping like a b!tch. I have personally seen boxes made out of diamond plate 1/4' aluminum with a lot or reinforcement and as a sealed enclsoure lined with a lot of dyna it works fine but ported it sounds bad, real bad... Polo.
Polo -- there is a huge difference between aluminum and hardened steel plate. The resonant frequency of plate steel is far above the cutoff point of these drivers. Like I said above, the main thing is to eliminate any metal-to-metal rattling in mounting the box and to tame the internal reflections by using generous amounts of polyfill.
